Dinghyman's first eBay link has the right description, and is for the flat-headed screws you want, but the photo looks wrong - the screws aren't long enough.
As an alternative, these from Farnell are right size, flat head, look right, but are plated brass, so if you want brass heads showing you'd have to abrade them - http://uk.farnell.com/tr-fastenings/m3-530-isbrmcn100/screw-slt-csk-brass-np-m3-5x30/dp/1420058